PLANTATION, Fla. – It was a celebration that fit the achievement. Francis Tiafoe slammed his racquet down and shouted up to the sky in elation.

Tiafoe, 15, won the boys’ 18s singles title at the Metropolia Orange Bowl International Tennis Championships on Sunday, becoming the youngest player to win the title in the tournament’s 67 years.

Tiafoe defeated Stefan Kozlov, of Pembroke Pines, Fla., 7-6, 0-6, 6-3, in the first all-American Orange Bowl boys’ final since 2004. It was also the first time two 15-year olds had played for the 18s championship – Tiafoe turns 16 on Jan. 20, Kozlov on Feb. 1 – with the College Park, Md., native writing history, with an exclamation point.

Serving for the match, Tiafoe boomed an ace down the middle, tossed his racquet and roared.

“Before serving, I was like, ‘I’m just going to hit it as hard as I can down the T,” Tiafoe said. “It doesn’t matter where it goes. I hit it as hard as I can, and it was probably the best serve I hit the whole match. It was unbelievable. I didn’t know what to do. I was too excited. I, like, slammed it. I never slammed a racquet from excitement before.”

Tiafoe, seeded 13th, defeated three of the tournament’s top five seeds en route to joining the likes of John McEnroe, Roger Federer, Ivan Lendl, Bjorn Borg and Andy Roddick as Orange Bowl champions. The only other 15-year old to win the boys’ 18s title is Sweden’s Kent Carlsson, who was 16 days older than Tiafoe when he won it in 1983.

On Sunday, Tiafoe battled from being down, 4-1, in the first set to claim it in a tiebreak. The pivotal moment came in the sixth game, on a fortunate mishit from Tiafoe that ballooned up to the sky and fell in. Shortly after, he won the rally, won the game then broke the fourth-seeded Kozlov to get back on serve.

“I came out really slow,” said Tiafoe, who trains out of the Junior Tennis Champions Center in College Park. “I was really tight. I was over-thinking the moment. He’s played a Grade A final before. He was looking pretty comfortable there. Even if I went down the first set, I kind of knew I would eventually get myself into it. He coughed up a couple of errors, and I felt pretty confident and ended up squeezing out that tiebreak.”

As Tiafoe put it, he “went cold” in the second set, and Kozlov took advantage. In the third, though, Tiafoe’s superior conditioning wore down Kozlov, the top-ranked American junior, who will end the year at No. 5 in the world junior rankings, two spots ahead of Tiafoe, who projects to jump from No. 35 to No. 7.

“I’ve had a really tough week, played some long matches. My body’s obviously not fully grown yet, and that’s going to be a huge role the next time you guys see me,” said Kozlov. “I’m going to be a lot stronger, and this won’t happen again. He’s in really good shape. I think if I played someone else, we would have been both dying.

“I don’t mind losing to him, because he’s a great player,” said Kozlov, who beat Tiafoe in their only previous meeting this year, in April’s International Spring Championships. “But I’ll get some revenge later.”

The girls’ 18s final also finished with intrigue. Top-seeded Varvara Flink, of Russia, defeated No. 2 Ivana Jorovic, of Serbia, 6-1, 2-6, 6-4. With Jorovic serving at match-point down, Flink hit her return into the net but pointed out to the chair umpire that the ball had torn open. By rule, the point was replayed, and Flink won the do-over.

“I was lucky with it, but that’s why I missed the ball, because I felt that it was broken. If the rally is done but the ball is broken, you replay the point,” said Flink, who will finish the year ranked No. 3 in the world among juniors. “It’s an unbelievable feeling, because I was really fighting for this match. My opponent was great and congrats to her for the final.”

In an entertaining boys’ 18s doubles championship, No. 2 Filippo Baldi, of Italy, and Lucas Miedler, of Austria, beat the top-seeded pair of Alexander Zverev, of Germany, and Andrey Rublev, of Russia, 6-3, 6-7 [10-8]. The pair also won the Eddie Herr International Championships last week.